If you live in the On Nut area of eastern Bangkok, and especially anywhere around the mouth of Soi On Nut 59 or deeper inside the soi, the last week of September 2026 is probably still vivid. According to a Thai PBS news report published on 29 September 2026 at 13:19, On Nut Road at Soi 59 still had roughly 20 centimetres of water standing on the road surface, several days after the heaviest rain had passed. This article is written specifically for the people who live and work along that soi. It explains which germs typically arrive with urban floodwater, why an ordinary clean-up with household products often leaves gaps, and exactly where the disinfection spraying service from World Health Disinfection (WHD) fits into getting a home safely back in use.

We will not simply say "On Nut flooded." Instead, we name the specific points where flooding was reported, how deep the water was and on which date, using only information from news reports and Bangkok Metropolitan Administration (BMA) announcements. That way you can judge for yourself how exposed your own house, townhouse or apartment building is likely to be.

A typical scenario (an illustrative example built from common situations, not a review from any specific customer)

Night three of the rain: water starts creeping under the door of a townhouse at the end of Soi On Nut 59

Ann is a 38-year-old accountant who lives in a two-storey townhouse deep inside Soi On Nut 59 with her 71-year-old mother and her five-year-old son. Between 24 and 27 September 2026 the rain barely stopped. On the third night, water from the road began spreading across the carport and then seeped through the gap under the front door into the ground-floor living room. It was only ankle-deep, but grey, full of leaves and plastic, and it smelled like a storm drain.

Ann carried the extension cords, a small sofa and her son's toy boxes upstairs. Her mother, who has diabetes and does not walk easily, moved to sleep in the upstairs bedroom. The family car spent two nights parked at a shopping centre near the mouth of the soi. Meanwhile Ann waded in and out of the soi twice a day in flip-flops.

When the water on On Nut Road began to drop on 29 and 30 September, the family scrubbed the floor with a lemon-scented floor cleaner, hosed down the carport and opened every door and window to let the damp out. Within two days the house looked tidy. Three days after that, her son developed loose stools and a low fever. Along the wall beside the staircase, a line of small black dots appeared just above the old waterline, and a musty smell drifted out every time someone opened the cupboard under the stairs.

Ann did the most important thing first: she took her son to a doctor. Then she started asking what was still left in a house that "looked clean." The answer was not that she had cleaned badly. Urban floodwater is a mix of rain, overflowing drains and household wastewater, and it leaves germs in tile grout, skirting boards and damp walls that ordinary floor cleaners are not designed to handle.

Where the water was: flood points in On Nut and nearby, according to news reports and BMA announcements

The information below comes from a Thai PBS report dated 29 September 2026 at 13:19 and a Dailynews report from the same day. Depth figures describe water on the road surface at the time of reporting. They are not the maximum depth inside any individual home; houses that sit lower than the road, or that are far down a soi, may well have had more.

• On Nut Road at Soi On Nut 59: about 20 cm of standing water on the road (Thai PBS, 29 Sep 2026, 13:19).
• Srinakarin Road between Phatthanakan and Sukhumvit 77: listed as a flood point. On Nut Road is itself Sukhumvit 77, so this stretch connects directly to the neighbourhood.
• Srinakarin Road between Lam Sali and Phatthanakan: another reported flood segment.
• Phatthanakan Road at the Srinakarin intersection: about 24.7 cm, the highest figure on that day's list.
• Phatthanakan Road at Soi 53: about 20 cm; Dailynews also named Phatthanakan 53 among the places where water remained high.
• Krungthep Kreetha Road: reported as flooded along its entire length.

The wider picture: from 24 to 27 September 2026 Bangkok received roughly 300 mm of rain in about 48 hours. On 26 September the BMA declared all 50 districts a disaster zone, and on 2 October 2026 the Department of Disaster Prevention and Mitigation reported about 329,000 Bangkok households affected. The eastern side of the city, including On Nut, Srinakarin and Phatthanakan, appeared on the reported lists again and again.

One thing On Nut residents know well is that the road is long and has a huge number of side sois, and their ground levels are not the same. Some housing estates were built on raised fill and sit above the road. Many older townhouses now sit below a road surface that has been raised several times, so they flood first and drain last. Twenty centimetres on the road may not sound like much, but water that stands for several days is enough to soak ground-floor walls, wooden doors, under-sink cabinets and laminate flooring.

The germs that follow a flood in On Nut: what arrives with the water and who is most at risk

The Soi On Nut 59 area is mainly residential: detached houses in gated estates, townhouses, shophouses with a business on the ground floor, and apartment blocks and dormitories for rent. Many households have small children and older relatives living under one roof. That mix means three groups of germs deserve special attention: germs from sewage-contaminated floors, germs that spread through children's hands and toys, and mold growing in ground-floor walls.

1. E. coli and other faecal bacteria

City floodwater almost always mixes with water from drains and overflowing septic tanks, so it commonly contains bacteria of faecal origin such as E. coli. When the water dries, these bacteria do not leave with it. They stay in the thin layer of silt on floors, in tile grout and on table legs. Toddlers who crawl or sit on the floor and then put their hands in their mouths have the highest chance of exposure. Symptoms include diarrhoea, cramps and sometimes fever.

2. Leptospirosis

Sois with markets, food stalls and rubbish collection points usually have rats. During a flood, urine from infected rats spreads through the water, and the Leptospira bacteria can enter the body through cuts on the feet, scratches or the eyes. People who waded in and out of the soi for days, like Ann in our example, are in the risk group. Sudden high fever, headache, muscle pain (especially in the calves) or red eyes within one to two weeks of wading is a reason to see a doctor immediately and to mention the flood exposure. Surfaces the water reached, such as carport floors, front gates and the lowest steps, also need thorough cleaning and disinfection.

3. Salmonella and contaminated food

Many soi homes store rice, dry goods and sauces in lower kitchen cupboards. If water reached those cupboards, the food should be thrown away, and kitchen surfaces such as counters, fridge handles and chopping boards must be washed and disinfected before anyone cooks again. Salmonella causes food poisoning with fever, diarrhoea and cramps, and it can be serious for older people and anyone with a chronic illness.

4. Norovirus and rotavirus

These two viruses are major causes of sudden diarrhoea. They spread easily via surfaces and close contact, especially in apartment blocks with shared bathrooms, corridors and lifts. If one person on a floor gets sick, others can follow quickly. Rotavirus is common in young children and can cause dehydration.

5. Hand, foot and mouth disease and RSV in children

The weeks after the flood fall in the rainy season, when hand, foot and mouth disease and RSV already circulate among children. When many children are crowded together at relatives' homes or go back to schools that have only just dried out, the risk rises. Toys, stair rails, door handles and dining tables are places where these viruses can linger.

6. Mold and musty smells

Soaked ground-floor plaster, gypsum board, wooden skirting and laminate can start growing mold within one or two days if they stay wet. The WHO and the US CDC advise cleaning and drying within 24 to 48 hours to limit mold. Spores can trigger allergies, asthma, chronic coughs and eye irritation. A musty smell that will not go away is a sign that moisture and mold are still hiding somewhere.

Who is most at risk: babies and toddlers, older adults, pregnant women, people with diabetes, kidney or heart disease, anyone with weakened immunity, and anyone with wounds on the feet or legs. If your household includes any of these people, the recovery should be more thorough than usual, and anyone with symptoms should see a doctor first. Disinfecting a home is never a substitute for medical care.

The real cost of the On Nut flood: health, money, time and family life

Health. Problems after the water goes down often arrive quietly. A child's diarrhoea, an older parent's cough, an itchy rash on the legs: each looks minor until you are taking time off work for the third trip to the hospital.

Money. A house on an On Nut soi that took even a few dozen centimetres of water faces bills for swollen wooden doors, new laminate flooring, repainting, washing machine and fridge repairs, plus taxis and parking fees while the soi was impassable. If mold spreads until walls or ceilings have to be opened up, the cost climbs sharply.

Time. Many families spend a week scrubbing, then repeat it when the smell returns.

Rental income. For owners of apartments and rooms for rent in the soi, the risk is tenants giving notice or posting in local online groups that the rooms smell damp and have mold, which can depress occupancy for months.

Family stress. Caring for an older relative and a toddler in a cramped upstairs room, and worrying the child will get sick again, wears everyone down.

Why the usual clean-up often falls short in Soi On Nut 59 homes

Floor cleaner is not a medical-grade disinfectant. Most household products are made to lift dirt and leave a pleasant scent, not to deal with heavy contamination from wastewater.

Bleach is awkward and not suitable everywhere. Diluted bleach can work on some hard surfaces when mixed correctly, but it has a harsh smell, irritates the airways, fades fabrics and some materials, and becomes dangerous if accidentally mixed with acidic toilet cleaners, which releases toxic gas.

Fans only dry the surface. A fan helps the surface dry faster, but it does not kill germs, and it can blow dried, contaminated silt dust around the house.

Air freshener hides the problem. A musty smell signals moisture and microbial growth; masking it lets the problem grow.

Painting over mold. It is a shortcut many people take, but if the wall is still damp inside, mold pushes the paint up into bubbles and returns within weeks.

Hands cannot reach everywhere. Under cabinets, behind the fridge, the gap between furniture and walls, under the stairs and inside the grooves of a sliding gate are all places a mop cannot reach but germs can.

How WHD post-flood disinfection spraying in On Nut works

According to the service information from World Health Disinfection, the disinfection spraying service is carried out by trained technicians using spraying and/or ULV (Ultra Low Volume) fogging. ULV turns the disinfectant into a very fine mist that settles on surfaces and reaches corners far more evenly than hand wiping.

The disinfectant is CHEMGENE HLD4H, a medical-grade disinfectant from the United Kingdom containing Benzalkonium Chloride and Didecyldimethylammonium Chloride, according to the service information. The service page lists viruses, bacteria and fungi it addresses, including COVID-19, RSV, H1N1, H5N1 and hand, foot and mouth disease virus, with a stated 99.99% efficacy. The page also lists approvals or endorsements from the Department of Medical Sciences (Thailand), Mahidol University, NHS England and the EN 14476:2013+A2:2019 standard.

The process

1. Book. Call 065-556-6294 or message LINE @whd268 with your address in Soi On Nut 59, the size of the property, number of floors and how high the water reached.
2. Prepare the area. Remove mud, rubbish and damaged items, wash floors and walls, and put away food, dishes and personal items.
3. Technicians spray. Everyone, including children, older relatives and pets, should leave the zone being treated.
4. Wait about 30 minutes, according to the service information, then return and use the space as advised by the technicians.

Let us be clear about one thing: disinfection spraying comes after mud removal and washing; it does not replace cleaning. Every disinfectant works best on a clean surface, and germs sitting under a layer of mud will not be reached. We also do not claim there is no residue at all. Always follow the re-entry time the technicians give you.

For rooms that still smell musty once closed up, such as ground-floor bedrooms or storerooms, you can consider residential ozone disinfection as a complementary service. Ozone treatment must be done in an empty room, with no people, pets or plants inside.

10 reasons homes in Soi On Nut 59 should be disinfected after the water goes down

1. Water that sat on On Nut Road for days was mixed with wastewater, not clean rain, so every surface it touched deserves professional disinfection spraying.
2. ULV mist reaches the hidden corners under cabinets, behind fridges, under stairs and inside gate tracks.
3. A medical-grade product. CHEMGENE HLD4H is used in healthcare settings, not an everyday floor cleaner.
4. Covers viruses, bacteria and fungi listed on the service page, which matches the mix of post-flood risks.
5. Lowers the risk for toddlers who play on the floor and for older relatives with weaker immunity.
6. Quick to complete. About 30 minutes of waiting per the service information, then re-entry as the technicians advise.
7. Helps landlords get rooms ready to rent and tell tenants honestly that the building has been disinfected.
8. References international standards including EN 14476:2013+A2:2019 and Thai and overseas bodies; see the details on the service page.
9. Experience with many building types. The service information lists hospitals, schools, malls, airports, offices, airlines, banks and residential buildings among its customers.
10. Tools to keep going yourself. The current promotion includes a free CHEMGENE spray bottle and WELLGIENIC wet tissues, and a tax invoice is available.

Before and after: a townhouse in Soi On Nut 59

Example case: a four-storey apartment block in the middle of Soi On Nut 59

Example case (a hypothetical scenario based on common problems, not a verified review)

Tom owns a 24-room apartment building halfway down the soi. The ground floor has six rental rooms, a shared laundry room and a lift lobby. Water from On Nut Road pushed into the lobby and the ground-floor rooms to about a hand-span deep and stayed for two days before slowly receding. Three ground-floor tenants went to stay with friends; the other three stayed but complained about the smell and the mosquitoes.

Once the water was gone, Tom hired two cleaners to shovel out the silt, scrub the lobby floor and wash the laundry room. He pulled off the swollen wooden skirting and ran industrial fans for three days. When the floors and walls had dried enough, he booked technicians to spray the whole ground floor, the lift lobby, the stair rails on every floor and the lift buttons. Tenants were told in advance when to stay out.

Tom also gained a clear story for his tenants. He pinned a notice by the lift listing what had been cleaned, what product was used, and advising anyone who had waded through floodwater and developed a fever to see a doctor. Two of the three tenants who had left temporarily decided to come back. For rooms that still smelled damp, he planned room-by-room ozone treatment while they stood empty.

On Nut post-flood recovery checklist: before and after spraying

Before the technicians arrive

• Switch off ground-floor power if sockets were submerged, and have an electrician check before use.
• Wear boots, rubber gloves and a mask while shovelling silt. Never wade through water or mud barefoot.
• Remove all mud and wash floors and walls with clean water and detergent.
• Throw away food, medicines and cosmetics that touched floodwater, plus soft toys and sponges that cannot be washed.
• Remove swollen wooden skirting, gypsum board or laminate so the wall behind can dry.
• Open doors and windows and use fans or a dehumidifier.
• Put dishes, cutlery, toothbrushes and personal items away in closed cupboards or boxes.

During and after spraying

• Everyone, including children, older relatives and pets, stays out of the zone being sprayed.
• Wait about 30 minutes per the service information and follow the technicians' re-entry time.
• Ventilate after you return.
• Rinse food-contact items again before use.
• Watch everyone's health for at least two weeks. Fever, calf pain, red eyes, severe diarrhoea or breathing difficulty means see a doctor immediately.
• Use the free spray and wet tissues on high-touch points regularly for the next few weeks.

FAQ: post-flood disinfection spraying in On Nut

Q: Water only reached the carport of my house in Soi On Nut 59. Do I need spraying?
A: If the water stayed in the carport and never came inside, you can choose to clean and disinfect just that zone. But check whether water seeped through doors or floors, and remember everyone walks through the carport daily and carries germs indoors on their shoes. The technicians can assess and suggest a sensible scope.

Q: Does the house need to be completely dry first?
A: Mud should be removed and surfaces washed and reasonably dry, because disinfectant works best without a thick layer of dirt. Spraying will not dry out soaked walls, so you still need ventilation and dehumidifying alongside it.

Q: Can we stay inside during spraying?
A: No one should stay in the zone being treated. Leave the area and return when the technicians say; the service page states a wait of about 30 minutes.

Q: Is there zero residue afterwards?
A: We do not make that claim. Ventilate after you return and rinse food-contact items before use. If there are infants or sensitive people at home, tell the technicians in advance so they can plan accordingly.

Q: Will spraying get rid of the musty smell?
A: Spraying deals with germs on surfaces, but if the smell comes from walls or ceilings that are still wet inside, the moisture has to be fixed too. For closed rooms where a smell lingers, ozone treatment may be a useful addition.

Q: My child has diarrhoea since the flood. What should I do first?
A: See a doctor first, especially with fever, frequent stools, weakness or signs of dehydration. Disinfecting the home helps reduce re-exposure but it is not treatment.

Q: Can an apartment owner get a tax invoice?
A: Yes. According to the service information, a tax invoice is available.

Book post-flood disinfection spraying in On Nut Soi 59 today

Tell us where in the soi your property is, how high the water came, and whether anyone at home needs extra care. The team will help you plan the right order of work for your home.

See the Disinfection Spraying Service

Call 065-556-6294 · LINE @whd268

Related links

• World Health Disinfection: disinfection spraying service
• CHEMGENE HLD4H disinfectant
• Residential ozone disinfection

References

• Thai PBS: Bangkok flood points, 29 Sep 2026
• Dailynews: Bangkok flood situation, 29 Sep 2026
• Post Today: Bangkok flood situation
• CDC: Floods and Your Health
• World Health Organization fact sheets
• Department of Disease Control, Thailand